1. Field of the Invention
The present invention relates to a light measuring and distance measuring apparatus for a camera capable of performing automatic exposure control and automatic focus adjustment and further having a focus locking function.
2. Description of the Prior Arts
Light measuring and distance measuring apparatuses for cameras are generally arranged such that brightness of an object and the distance to it (or focus condition of the photographic lens relating to it) are measured (or detected) and thereby a suitable exposure value and focusing of the lens to obtain an in-focus condition are automatically set therein immediately before a shutter release for taking a photograph. Of such apparatuses, there is known a type adapted, for convenience of operation, such that the light measuring and distance measuring and further, exposure calculation and automatic focus adjustment to the object are performed by depressing the release button to a first step (halfway), and by keeping the button depressed to the first step, the in-focus condition to the object can be locked and the exposure value can also be locked (AE lock) at that time.
When the object is moving with changing its position momentarily, conditions of the magnitude (magnification of the image) and brightness of the object change in many cases. In such cases, if the AE lock is performed at the same time when the in-focus condition obtains, it frequently occurs that an unsuitable exposure value is obtained.